Joe Biden condemns Trump's handling of North Korea

In a wide-ranging interview with PBS NewsHour's Judy Woodruff, former Vice President Joe Biden said he believes the U.S. is closer than ever to nuclear war, adding President Trump "undermines" the office of the president. He also talks about his latest book, "Promise me, Dad," which chronicles his son Beau's brain cancer diagnosis and death, and his own decision not to run for president in 2016.